Microsoft Sharepoint Products and Technologies Resource Kit eBook

110 Part II: SharePoint Products and Technologies Architecture
Saving Database Space
The content database of a site includes a documents table that contains a record for
each page created in a site. Considering the number of sites and pages that Windows
SharePoint Services can support, the number of records in this table can be
quite large. Even though the number of records is large, Windows SharePoint Services
keep the overall size of the table low by keeping each record in the table relatively
empty by default. When a page is created by using a template, the record in
the content database for that page contains only the location of the template used to
create the page. The record does not contain any customization data for the page.
The customization of each site’s page occurs only during the rendering process.
During this process, a navigation control looks to the URL of the page and
finds the name of the site. The control uses the site name to find customization information
in the content database and makes these customization changes before the
page displays. In essence, each page that is based on the same template is the same,
but users do not realize this because of customizations made during the rendering
process.
Increasing Performance
The use of templates also allows ASP.NET pages to run as they were designed. Normally,
an ASP.NET page is read and then saved to a DLL file on the local computer.
Subsequent requests for that page are handled by running the DLL off the local file
system. In Windows SharePoint Services, this is called direct mode. Site pages that
are based on templates run in direct mode. A DLL only needs to be created for each
template instead of for each site’s version of the page. It would not be practical to
have a DLL read into memory for each site’s version of a page.
The Effects of Customization
The performance enhancements in the architecture of templates and site pages
based on templates are lost once a site page is customized. Once the code of a site
page is edited and saved, it can no longer use the template to load.
Once this occurs, Windows SharePoint Services changes the site page’s record in
the documents table of the site content database. It replaces the location of the template
in the site pages record with a copy of the entire page. Also, because only templates
can run in direct mode, from that point on the page must be run in safe mode.
The Web.Config File
The Web.config file is an XML-based text file that contains configuration information
for ASP.NET services. There are multiple Web.config files in Windows Share-
Point Services. In a Windows SharePoint Services deployment, Web.config files are
contained in the following folders within the file system: